Contribution of mineral nutrition to the response of barley seedlings to polyethylene glycol–induced mild water stress

2007 ◽  
Vol 170 (3) ◽  
pp. 392-397 ◽  
Author(s):  
Konstantina V. Kocheva ◽  
Georgi I. Georgiev ◽  
Reneta V. Vunkova-Radeva
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Mineral Nutrition ◽  
Mild Water Stress

scholarly journals Photosynthetic parameters and growth in seedlings of Bertholletia excelsa and Carapa guianensis in response to pre-acclimation to full sunlight and mild water stress

2014 ◽  
Vol 44 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Gracilene Fernandes da Costa Azevedo
Keyword(s):  
Water Stress ◽  
Higher Plants ◽  
Field Capacity ◽  
Outdoor Exposure ◽  
Photosynthetic Parameters ◽  
Bertholletia Excelsa ◽  
Full Sunlight ◽  
Carapa Guianensis ◽  
Light Levels ◽  
Mild Water Stress

Light and water are important factors that may limit the growth and development of higher plants. The aim of this study was to evaluate photosynthetic parameters and growth in seedlings of Bertholletia excelsa and Carapa guianensis in response to pre-acclimation to full sunlight and mild water stress. I used six independent pre-acclimation treatments (0, 90 (11h15-12h45), 180 (10h30-13h30), 360 (09h00-15h00), 540 (07h30-16h30) and 720 min (06h00-18h00)) varying the time of exposure to full sunlight (PFS) during 30 days, followed by whole-day outdoor exposure for 120 days. Before PFS, the plants were kept in a greenhouse at low light levels (0.8 mol m-2 day-1). The PFS of 0 min corresponded to plants constantly kept under greenhouse conditions. From the beginning to the end of the experiment, each PFS treatment was submitted to two water regimes: moderate water stress (MWS, pre-dawn leaf water potential (ΨL) of -500 to -700 kPa) and without water stress (WWS, ΨL of -300 kPa, soil kept at field capacity). Plants under MWS received only a fraction of the amount of water applied to the well-watered ones. At the end of the 120-day-period under outdoor conditions, I evaluated light saturated photosynthesis (Amax), stomatal conductance (g s), transpiration (E) and plant growth. Both Amax and g s were higher for all plants under the PFS treatment. Stem diameter growth rate and Amax were higher for C. guianensis subjected to MWS than in well-watered plants. The contrary was true for B. excelsa. The growth of seedlings was enhanced by exposure to full sunlight for 180 minutes in both species. However, plants of B. excelsa were sensitive to moderate water stress. The higher photosynthetic rates and faster growth of C. guianensis under full sun and moderate water stress make this species a promissory candidate to be tested in reforestation programs.

Improving water stress tolerance of the biocontrol yeastCandida sakegrown in molasses-based media by physiological manipulation

2001 ◽  
Vol 47 (2) ◽  
pp. 123-129 ◽  
Author(s):  
M Abadias ◽  
N Teixidó ◽  
J Usall ◽  
I Viñas ◽  
N Magan
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Amino Acid ◽  
Cell Viability ◽  
Stress Tolerance ◽  
Biocontrol Agent ◽  
Compatible Solutes ◽  
Intracellular Concentration ◽  
Water Stress Tolerance ◽  
Candida Sake

The biocontrol agent Candida sake was cultured on either an unmodified molasses-based medium (water activity, aw0.996) or on water stressed media produced by the addition of glycerol, glucose, NaCl, sorbitol, or proline to 0.98, and 0.96 awfor 24, 48, and 72 h, to study their impact on subsequent cell viability, and on concentrations of endogenous sugars (trehalose and glucose) and polyols (glycerol, erythritol, arabitol, and mannitol). The viability of cells of different ages cultured on these media was evaluated on NYDA medium with freely available water (aw0.995), and on medium modified with polyethylene glycol to aw0.95. Regardless of solute used, viable counts of cells grown on molasses-based medium (aw0.98) were equal to or higher than those obtained from the medium with water freely available. The amino acid proline stimulated growth at 10% concentration. In contrast, water stress induced by addition of NaCl, glucose, or sorbitol at aw0.96 caused a significant reduction in viable counts. Older cultures were more resistant to water stress. Glycerol and arabitol were the main solutes accumulated by C. sake cells in response to lowered aw. Intracellular concentration of these polyols depended more on the solute used to adjust the awthan on the awitself. Candida sake was more resistant to water stress with higher intracellular concentration of glycerol and erythritol.Key words: compatible solutes, polyols, sugars, improved viability, formulation.

Influence of elevated CO2 and mild water stress on nonstructural carbohydrates in field-grown cotton tissues

1994 ◽  
Vol 70 (1-4) ◽  
pp. 153-162 ◽  
Author(s):  
D.L. Hendrix ◽  
J.R. Mauney ◽  
B.A. Kimball ◽  
K. Lewin ◽  
J. Nagy ◽  
...  
Keyword(s):  
Water Stress ◽  
Elevated Co2 ◽  
Nonstructural Carbohydrates ◽  
Mild Water Stress

Effects of water potential on germination of lettuce, sunflower, and citrus seeds

1969 ◽  
Vol 47 (11) ◽  
pp. 1761-1764 ◽  
Author(s):  
Merrill R. Kaufmann
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Water Potential ◽  
Cellulose Acetate Membrane ◽  
Lettuce Seeds ◽  
Water Potentials ◽  
Citrus Seeds ◽  
Germinating Seeds ◽  
Polyethylene Glycol 6000 ◽  
Selection Of

The effect of nearly constant water potential on germination of citrus, sunflower, and lettuce seeds was studied. Water potential equilibration was achieved by placing soil above a cellulose acetate membrane which was in contact with a solution of polyethylene glycol-6000. Selection of solute potentials in the solution resulted in controlled water potentials in the soil over a range of 0 to −14.9 bars for citrus and 0 to −8.0 bars for sunflower and lettuce. The water stress experienced by germinating seeds in this system is largely the result of a matric effect rather than a solute effect.Citrus seeds germinated at water potentials as low as −4.7 bars and lettuce at −4.1 bars, but sunflower germinated at −8.0 bars. Sunflower germinated as rapidly at −4.1 bars as lettuce at −2.3 bars, both reaching 50% germination at about 8 days. Citrus germinated much more slowly, requiring 26 days at 0 bars.

scholarly journals Effects of Water Stress on Germination of Yarrow Populations (Achillea Spp.) From Different Bioclimatic Zones in Iran

2014 ◽  
Vol 68 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Parvin Salehi Shanjani ◽  
Masoumeh Izadpanah ◽  
Mohamad Reza Mohamadpour
Keyword(s):  
Polyethylene Glycol ◽  
Natural Selection ◽  
Water Stress ◽  
Water Potential ◽  
Wild Populations ◽  
Genetic Potential ◽  
Intraspecific Variations ◽  
Germination Ability ◽  
Genetic Pool ◽  
Polyethylene Glycol 6000

ABSTRACT The effects of water potential on germination were studied in 18 wild populations of three yarrow species (Achillea tenuifolia, A. vermicularis and A. filipendulina) from different bioclimatic zones in Iran. Water potential between 0 and -0.6 MPa were obtained using polyethylene glycol 6000 (PEG-6000) solutions. The study of water stress on germination showed that, regardless of the species and the populations, the lowering of the water potential reduced the capacity for germination and early seeding growth. These results indicated a strong genetic potential for drought tolerance during germination within each species. These differences in germination ability of wild populations of each species might be attributed to intraspecific variations resulting from the effects of natural selection and genetic pool background.

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